Sultan Han is a large Seljuk Caravanserai located in the town of Sultanhanı. It is one of the three monumental caravanserais in the neighbourhood of Aksaray.
This fortified structure was built in 1229 during the reign of the Seljuk sultan Kayqubad I along the trade route from Konya to Aksaray, leading to Persia. This monumental caravanserai became the largest in Turkey. It is one of the best examples of Anatolian Seljuk architecture: http://en.wikipedia.org/wiki/Sultan_Han